Inductive load driver slew rate controller
AssigneeMicrochip Technology Incorporated
InventorsBart De Geeter, Nicolas Furrer
Life of this patent
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Abstract
A circuit and method for digital controlling the slew rate of load voltage are provided. The circuit is comprised of a digital slew-rate control unit that utilizes a feedback signal to generate control signals where the feedback signal indicates the observed rate of voltage change on the load. The circuit is further comprised of a load driver circuit that is operated by the control signals and provides a slew-rate controlled output voltage used to operate a load switch, where the load switch provides power to the load. The circuit is configured to operate the load switch using a slew-rate controlling driver, depending on the state of the load switch transition, and a non-controlling driver.
Claims24
An integrated circuit for driving a first load switch wherein the first load switch powers a current load, the integrated circuit comprising:
- a first digital slew-rate control unit for generating control signals, wherein the first digital slew-rate control unit receives a first input signal and generates first control signals based on the first input signal and a feedback signal that indicates the rate of voltage change on the load;
- and
- a first load driver circuit operated by the first control signals and the first input signal, wherein the first load driver circuit comprises a large low impedance driver receiving said first control signals and a small current limited driver receiving said first input signal, wherein an output of the large low impedance driver is coupled with the output of the small current limited driver to generate a slew-rate controlled first output voltage for operating the first load switch.
A slew-rate controlled load driving system comprising:
- a first and second load switch coupled in series for powering a current load connected to a node between the first and second load switch;
- a first digital slew-rate control unit that generates control signals, wherein the control signals are generated based on a feedback signal that indicates the rate of voltage change on the load;
- a first load driver circuit operated by the first control signals and the first input signal, wherein the first load driver circuit comprises a large low impedance driver receiving said first control signals and a small current limited driver receiving said first input signal, wherein an output of the large low impedance driver is coupled with the output of the small current limited driver to generate a slew-rate controlled first output voltage for operating the first load switch,
- a second digital slew-rate control unit for generating control signals, wherein the second digital slew-rate control unit receives a second input signal and generates second control signals based on the feedback signal that indicates the rate of voltage change on the load;
- and
- a second load driver circuit operated by the second control signals and the second input signal, wherein the second load driver circuit comprises a large low impedance driver receiving said second control signals and a small current limited driver receiving said second input signal, wherein an output of the large low impedance driver is coupled with the output of the small current limited driver to generate a slew-rate controlled second output voltage that operates a second load switch coupled in series with said first load switch.
A method for controlling the slew rate of a first load switch, wherein the first load switch powers a current load, the method comprising:
- receiving a first input signal;
- generating, via a first digital slew-rate control unit, first control signals, wherein the first digital slew-rate control unit generates the first control signals based on the first input signal and a feedback signal that indicates the rate of voltage change on the load;
- generating a slew-rate controlled first output voltage via a first load driver circuit, wherein the first load driver circuit is operated by the first control signals and the first input signal, wherein the first load driver circuit comprises a large low impedance driver receiving said first control signals and a small current limited driver receiving said first input signal, wherein an output of the large low impedance driver is coupled with the output of the small current limited driver to generate the slew-rate controlled first output voltage;
- and
- operating the first load switch using the slew-rate controlled first output voltage.
Dependencies are inferred from the claim text.